After earlier-egg guidelines, egg allergy fell from 9.2% to 7.6% — and from 35% to 22% in infants with eczema

Design

Repeated cross-sectional population study with oral food challenge, 2007–11 vs 2018–19

Population

7,209 infants aged 11–15 months at immunisation visits, Melbourne

Primary outcome

Challenge-confirmed egg allergy prevalence

Effect

9.2% to 7.6% (−1.6 points, 95% CI −3.3 to −0.005); eczema 34.6% to 21.9%

Researchers in Melbourne recruited two population-based samples of infants at their 12-month immunisation visit using identical methods: 5,276 in 2007–2011, before Australian guidelines changed to advise earlier egg introduction, and 1,933 in 2018–2019, after. Every infant had a skin prick test to egg; those positive had an oral food challenge.

Median age at egg introduction fell from 8 to 6 months. After adjusting for known allergy risk factors, egg allergy prevalence fell from 9.2% to 7.6% (absolute difference −1.6 points, 95% CI −3.3 to −0.005). In infants with early eczema, it fell from 34.6% to 21.9% (−12.7 points, −20.0 to −5.4).

Randomised trials had shown that earlier egg introduction prevents allergy; this shows the effect reaching the population once the advice was followed. The overall reduction is modest and its confidence interval only just excludes zero, but the effect in infants with eczema — the group guidelines target — is large. The practical message is to make early egg introduction routine advice at every infant contact, not something left to parents to discover.

• Advise every family to introduce well-cooked egg at around six months as part of weaning.
• Prioritise infants with early eczema, in whom allergy fell by about a third.
• Do not routinely test for egg allergy before introduction in infants without a reaction history.
• Use the six-month immunisation visit to give feeding advice.
• Refer infants who have already reacted to egg for specialist assessment rather than advising avoidance alone.

Why it matters

It shows the trial-proven benefit of early egg introduction translating into fewer allergic children at population level.

Don't overread it

A before-and-after comparison cannot fully exclude other changes over the decade; the overall reduction only just reached statistical significance.

The statistics, in plain English

The overall confidence interval (−3.3 to −0.005 points) barely excludes no change, so the population effect is real but its size uncertain. The eczema subgroup interval (−20 to −5 points) is well clear of zero.

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